A Wideband Circularly Polarized E-Band SIW-Fed Antenna Array with High Efficiency

This article mainly proposed a wideband circularly polarized (CP) dipole element, fed by substrate integrated waveguide (SIW) used for E band communications. The magnetoelectric (ME) dipole consists of two C-shaped folded arms excited by a slit, and the length of the dipole is nearly twice the wavelength. To realize more overlapping bandwidth, a rotating feed technique is used to build a $\mathbf{2} \times \mathbf{2}$ small array, improving the overlapping bandwidth to 36%, equal to the impedance bandwidth of the subarray. Finally, based on the subarray, a $4 \times 4$ array is constructed. It arrived a nice impedance bandwidth of 32.8% (63.05-87.8 GHz), a wide ARBW of 43.4% (58.23-90.55 GHz), a 3 dB gain bandwidth of $\mathbf{3 7. 8 \%}$, and a maximum antenna gain of 18.7 dBi. In addition, the radiation efficiency in the working band is about $\mathbf{9 0 \%}$. Therefore the proposed antenna has great application potential in E-band communication.